Is it possible to distinguish the call notes of Audubon’s vs. Myrtle Yellow-rumped Warbler during the non-breeding season where they occur together?

Answer:

Obviously, these birds are NOT singing during the non-breeding season, but you do often hear loud chip or call notes where Audubon’s and Myrtle Yellow-Rumped Warbler patrol during the non-breeding season.

In many cases you can hear how the Myrtle (one of the subspecies of the Yellow-rumped Warbler species) has a flatter and softer chip note than the Auduon’s.

The “ch” component of the call note is weaker for the Myrtle and it often gives many calls in rapid succession.

However, be careful. Intergrades (individuals that display visual characteristics specific to both Audubon’s and Myrtle) may announce call notes of the other subspecies. In other words, it’s possible to see a bird that looks like an Audubon’s, but it’s call note sounds like a Myrtle. This individual could likely be an intergrade.

Warbler Guy: "Is your Warbler Watch different than Cornell's?"

(Thanks for the question, Sharon D. in Mequon, WI.)

Cornell Lab of Ornithology's "Warbler Watch" monitoring project is admirable and deserves kudos.

Visit:

http://www.birdsource.org/warblers/IDguide.html

Here, you'll see an interactive sight at which you can navigate to learn about and view most New World wood-warblers (Parulidae family members).

That written, Cornell's effort postdates my WarblerWatch blog site here -- and my focus is on answering your questions about wood-warblers and/or highlighting them with essays/articles and photos.

Ultimately, both Warbler Watch efforts attempt to educate people about the beauty and importance
of wood-warblers -- and saving their populations (including the federally endangered Kirtland's Warbler, a male of which is shown in the nearby photograph).

What could be more important conservation efforts?

Thus, I applaud Cornell's Lab of Ornithology staff -- and keep up the good work.